Extension ladder.



W. G. BEATTY.

EXTENSION LADDER.

APPLICATION FILED OCT- 9, 19x2. RENEWED DEC. 2a, 1915.

1,170,395. Patented Feb. 1, 1916.

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ii rr STATES PATENT onrron WILLIAM GEORGE ZBEATTY, 0F FERGUS, onTAmoJcnmAum. 1

EXTENSION-LADDER.

Specification- 0f Letters Patent.

Manama. 1,1916;

Application filed October 9, 1912, Serial Nave-mas. Renewed December'23, 1915. seriai xo. 68,460.

To all whom it may concern: I

Be it known that I, W1LLIAM GEORGE BEATTY, .of the town of Fergus, in the county of Wellington, in the Province ofv the purpose of holding the extension units a in their elevated positions. Heretofore these locking members have been pivotedto the risers of the extension units near their lower ends, so as to swing by gravity into operative relation with the rungs of the ladder units below them, and in the lowering of the extension units, these locking members owing to their gravital character, swung into engagement with the rungs as theextension unit descended, and causedthe user to manually release the locking members therefrom.

The object of my present invention is to provide these locking members with gravity latches projecting into the path of the rungs as the extension unit descends and moved by said rungs to close the rung-entrances to the gripping elements of said locking members during such descent, and droppinginto an inoperative position to open said en'- trances when the extension unit rises.

For an understanding of the invention, reference is to be had to the following description and to the accompanying drawings, in which;

Figure 1, is a front elevation showing the use of the invention; Fig. 2, is a section of the line 06-64 Fig. 1, showing the locking member engaging with a ladder rung, and the pivoted latch in an inoperative position; Fig. 3, is a similar view to Fig. 2, showing the position of the locking member and pivoted latch when the extension unit is being raised; Fig. 4, is a similar view to Figs. 2 and 3, showing the position of the locking member and pivoted latch when the extension unit is being lowered; Fig. 5, is a front elevation of the casing for the looking member; Fig. 6, is a side elevation of the construction shown in Fig. 5; Fig. 7, is a section showing the locking member and riser; Fig. 8', is an edge elevation 'ofthe' construction shown 'in Fig. "2'.

Like characters of referencerefer to like parts throughout the specification and drawings. i

The extension unit consists of 'a set of risers a and a p'l'ura-l number of -rungs b, b". Pivoted to the inner face of each rise-r a near the lower end thereof, is a locking upper end, for the pivot e to pivotally con- 'nect it to the riser. The body of the locking member 0 is apertured as shown at f and g, for the purpose hereinafterjdescribed. At the lower left-hand corner of'the looking member a i substantially U. a g pping element It to engage with thez' of the ladder unit j, the right side of the gripping element in being elongated as shown at h and formed with an angularextension 72/ having a downward inclination to the right for the purpose hereinafter described.

Pivoted to the side h of'the gripping greater than the distance across the entrance Z of the gripping element.

Partly covering the locking member 0 is.

a case 0, having at its top end an inwardly arranged ofi'set p, and near. itslowerend. a

boss 4, the inner face of "which is in the same element is a latch Z0. of a length slightly 0 are secured to the riser a, the boss 9 extends ment of said locking member without impedance by the rung b.

In the use of the invention the locking members 0 and casings 0 are'secured to the inner faces of the risers near their lower ends as above described, and when the ladder units are in an inclined position, which is their normal position when set up, the looking members 0 swing to the left from the pivot bolts 6 and bring the gripping elements it into position to engage the rungs 2'.

When the extension unit is moving upward, as shown in Fig. 3, the latch 70 assumes the position shown in that'figure and in Fig. 7 and leaves the entrances Z to the gripping elements it, open so that when the gripping elements are raised slightly above the rung z, and then lowered into the position shown in Fig. 2, the rung 2' will enter the gripping element and be engaged thereby and the locking members will then hold the extension unit in its elevated position.

To lower the extension unit, the latter is raised until the gripping elements it are slightly above the ladder rung i, and then the locking members are moved to the right until they are entirely free of the rung 2'. The extension unit is then lowered, as shown in Fig. 3, and as it descends, the rungs below it successively engage the angular extensions h which automatically move the locking members to the right, and thus preventrthe rungs i getting behind them to impede the lowering movement of the extension unit. The latches 70, then coming into engagement with the successive rungs as shown in Fig. 4, are moved by them to close the entrances Z to the gripping elements and prevent them engaging any of the lower rungs during the lowering movement of the extension unit, the latches 7: as they pass each rung automatically opening by gravity into the position shown in Figs. 3 and 7. In this way,

the extension units can be lowered to their full length without any 'possibility of the gripping elements engaging with any of the lower rungs during the lowering movement of the extension units.

If it is desired to lower the extension unit from any elevated position to any other elevated position on a lower plane, the moclus opewmcli described is carried out until the locking members a have descended below the desired rung. The extension unit is then raised until the gripping elements it are slightly above said rung, when the locking members 0 will automatically swing by gravity to the left and then when the extension unit is lowered the gripping elements will engage it, the latches 70 during this upward movement of the extension unit remaining in the position shown in Figs. 3 and 7.

Having thus fully described the nature of my invention, what I claim as new and desire to secure by Letters Patent, is

In an extension ladder, a locking element so pivoted to an extension ladder section as to tend to swing toward an adjoining ladder section and having at its lower end a substantially U-shaped rung-gripping member, one side of which is elongated and is provided with an angular extension having a downward inclination from the entrance to the rung-gripping member to engage the ladder rungs and move the locking element to the proper side thereof for the unimpeded descent of the extension section, and a latch pivoted to said angular extension to close the entrance to the rung-gripping member.

Fergus, September 21st, 191:2.

WILLIAM GEORGE BEATTY.

Signed in the presence of A. C. DEACON, R. D. KERR.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. C. 

